Facile formation of nanoporous reduced graphene oxide via epoxy-based negative photoresist laser irradiation for highly sensitive and selective gas detection

Abstract

This study aims to advance gas sensor technology, particularly focusing on chemiresistive gas sensors known for their simplicity and cost-effectiveness. SU-8, an epoxy-based negative photoresist characterized by the presence of eight epoxy groups, is employed as a precursor to laser-induced graphene. Under CO2 laser irradiation, SU-8 rapidly dissociates, forming a porous graphite-like surface and transforming into reduced graphene oxide (rGO). This rGO exhibits exceptional sensitivity, detecting 20 ppb of NO2 at room temperature (25 degrees C), representing a significant achievement for singular materials. Furthermore, the study demonstrates the scalability of rGO not only as a sensing material but also as a framework through a straightforward deposition process. The deposition of SnO2 on rGO shows remarkable selectivity and sensitivity toward NO2 gas, achieving an ultra-low limit of detection of 26.2 ppt. Subsequent Pd deposition enhances the gas sensor's selectivity for hydrogen gas, highlighting its scalability as a framework for diverse gas sensors beyond NO2. In summary, this study showcases the capability of carbonized SU-8 to detect low-concentration NO2 using a singular material. It underscores the material's potential as a versatile framework for gas sensors, demonstrating its adaptability across various gas sensing applications.